Omphalos

An omphalos is a religious stone artefact in the ancient world. In Greek, the word omphalos means "navel".

According to the ancient Greeks, Zeus sent out two eagles to fly across the world to meet at its center, the "navel" of the world. Omphalos stones to denote this point were erected in several areas surrounding the Mediterranean Sea, the most famous of those at the oracle in Delphi. Omphalos stones were said to allow direct communication with the gods.